Anxiety disorders are one of the most common mental illnesses in children and are associated with symptoms causing impairment and poor functioning. Effective early treatment of anxiety may reduce its negative impact and reduce its persistence into young adulthood. The antidepressant class selective serotonin reuptake inhibitors (SSRIs) are recommended as the first line medication treatment for children with functional impairing anxiety disorders, based on randomized controlled trial evidence. It is unknown whether children with anxiety initiate prescription medication concordant with guidelines. The burden of serious adverse outcomes in children with anxiety is also unknown. Given that the combination of cognitive behavioral therapy and SSRIs has been shown to offer an advantage over SSRIs alone and psychotherapy alone in treating children with moderate to severe anxiety, it is hypothesized that children receiving combination therapy may experience reduced serious adverse outcomes compared to children on mono-therapy. Increased contact with a healthcare provider (i.e. children on combination therapy) may also result in improved medication adherence. The proposed study will describe prescription medication utilization for anxiety, how long the medications are taken, and the frequency in which psychotherapy is used surrounding medication initiation in children (3-17 years) with a non-OCD anxiety diagnosis from 2004-2013 (Aim 1). The rate of serious adverse outcomes in children with anxiety and whether serious adverse outcomes vary by treatment type: combination therapy (SSRI + psychotherapy) vs. SSRI mono-therapy and psychotherapy mono-therapy, and whether results differ by co-morbid depression status will be estimated (Aim 2). The serious adverse outcomes evaluated will include treated self-harm events, mental health related hospitalizations, and emergency room visits. Lastly the proposed study will estimate SSRI adherence in children with anxiety and whether adherence varies between children on combination therapy vs. SSRI mono-therapy (Aim 3). The proposed observational study will utilize an administrative claims datasource providing a real world population, adequate sample size, and longitudinal data to effectively and efficiently address the study questions. Results from this study will inform further work and will assist providers, patients, and caregivers in optimizing treatment to minimize the risk of serious adverse outcomes.